This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. This subproject is aimed at determining the structure of the E. coli 70S ribosome in different steps of translation elongation, termination and ribosome recycling. Atomic-resolution structures of the bacterial ribosome in these various steps of translation will aid in the the future development of antibiotics that target the ribosome.